Keep in mind regarding ramp control....they are NOT air traffic controllers.

In most cases they are airline personnel who work for the major carrier at the airport or terminal. They are not subject to the same regulations as air traffic controllers and in some cases are instructed NOT to use ATC phraseology. They have direct shout-lines to the Ground positions in the control tower and they coordinate with ATC on a regular basis. They even have Letters of Agreement with ATC facilities to define and clarify responsibilities.

In CLT the ramp tower is located directly above the main atrium of the terminal. They handle traffic from the entry/exit spots to the gates. I believe the express concourse flights are handed off to the north ramp frequency when they cross the intermediate hold line. It really is quite interesting listening to the fine USAirways staff handling the ramp functions.

If you listen to Boston, you'll hear Clearance Delevery either ask planes to "monitor ground for the push" or "contact the ramp for push", depending on where they're parked. So they have a split system.

I have yet to find a good gate chart of KBOS. Anyone know where to locate one?

There's also usually minimal coordination between ATC and airline ramp controllers - although there are airline personnel that coordinate with ATC. If you listen to JFK ground enough you will hear them complain about the JetBlue ramp controllers. I have also witnessed really poor errors of judgment by ramp controllers, such as pushing an a/c back while an emergency aircraft (with a sick passenger) is trying to pull into the ramp. This happens fairly often, I recall reading about a more serious incident where an a/c with a hemophilic child, bleeding out, was trying to return to the ramp, and ramp knowing this pushed another a/c out while the emergency a/c was trying to get back in; blocking the alleyway.

Ramp controllers are usually (not always) airline employees, but are almost never FAA Air Traffic Controllers. Depending on the airport, coordination between Ramp and Ground is usually pretty good (except for JFK, which has its own challenges). Here are some ramp controlled airports that I've worked/visited:CVG - Comair has 2 ramp controllers, Delta has 2 ramp controllersBOS - Delta controls the area past K4 in the main/satellite/B terminal areaJFK - numerous ramp controllers by numerous airlinesORD - numerous ramp controllers by numerous airlinesMCO - Delta controls their airside ramp area (I'm not sure who controls the other airsides)LGA - numerous ramp controllers by numerous airlinesATL - numerous ramp controllers (I think they are Delta employees, but not 100% sure)CLT - 2 USAirways ramp controllers

Is an airline employed ramp controller a peculiarly American thing or does anyone know of any non-US examples? As far as I know most places elsewhere use ATC Ground Control for the same functions (like the smaller US airports I guess). Please correct me if I am wrong.

Ive been listening the KPHL tower feed and noticed that after some taxi instructions they say contact the ramp on so and so frequency. Why do they do this there, and not at say KJFK for example? Or at least I havent heard it.

There are so many different ramp control frequencies that the ground controllers would have a tough time keeping up with it. It's purely an airline organizational thing to contact ramp control (ie there is nothing legality-wise that says you must). Every ramp at JFK is controlled by ramp controllers.